It is known to make wound dressings for use on exuding wounds. Such dressings manage the exudate produced by the wound in a variety of ways. For instance, some dressings, mainly those based on foam, manage exudate by absorbing the exudate and allowing the moisture taken up by the dressing to evaporate through the backing or top of the dressing. Such dressings are not designed to absorb and retain the exudate but to absorb and expel the exudate by moisture vapour transmission so that they maximise the level of exudate handled within the limitations of their design. A disadvantage of such dressings is that the lateral spread of the exudate across the dressing is not contained because of the nature of the open structure of the foam and this can cause normal skin surrounding the wound to become macerated as the whole of the dressing surface becomes saturated.
A further disadvantage of the open structure of the foam is that when the dressing is put under pressure, for example when compression is applied or when force is applied to the dressing due to the patient sitting, lying or rolling over, the exudate can be squeezed out of the porous, open foam structure and into contact with the wound and/or surrounding skin surfaces creating the potential for peri-wound maceration and, in the case of chronic wounds, further wound breakdown due to damage caused by certain components of chronic wound exudate.
A further disadvantage of such dressings is that rapid loss of exudate by evaporation can cause the wound surface to become desiccated over time which impedes healing.
Other dressings, mainly those based on absorbents that gel, manage exudate by absorbing it and retaining it within the dressing. The moisture in the absorbent can still be lost by vapour transmission from the dressing, but less readily than with a foam absorbent because the exudate is retained and held within the gelled absorbent. As the absorbent is acting as a reservoir for exudate, it needs to have sufficient capacity to retain exudate throughout the wear time of the dressing. This affects the quantity of absorbent needed in the wound dressing which of course affects the thickness and conformability of the dressing overall. In addition, in general with gelling absorbents, particularly fibrous gelling absorbents, the relationship between the thickness of the gelling absorbent layer or its weight per unit area and its absorbency is not linear. This means that a careful balance needs to be struck between absorbency, conformability and moisture vapour transmission.
There is a need for an absorbent component for use in wound dressings which is capable of absorbing exudate at the rate at which it is produced by the wound, which also does not cause maceration to the wound and skin surrounding the wound, which gives a reasonable wear time before needing to be replaced and which is conformable.